1. Field of the Invention
The present invention relates to fracturing subterranean formations to increase the production of oil and gas therefrom, and more particularly, to breaker activators for use in low temperature formations.
2. Description of the Prior Art
Hydrocarbon producing wells are often stimulated by hydraulic fracturing treatments. In hydraulic fracturing treatments, a viscous fracturing fluid which also functions as a carrier fluid is pumped into a producing zone to be fractured at a rate and pressure such that one or more fractures are formed in the zone. Particulate solids, e.g., graded sand, for propping the fractures, commonly referred to in the art as proppant are suspended in the portion of the fracturing fluid so that the particulate proppant material is deposited in the fractures when the fracturing fluid is broken. That is, a delayed viscosity breaker is included in the fracturing fluid whereby the fracturing fluid reverts to a thin fluid which is returned to the surface. When the fracturing fluid is broken, the particulate proppant material is deposited in the fractures and functions to prevent the fractures from closing so that conductive flow channels are formed through which produced hydrocarbons can readily flow.
In some hydrocarbon producing subterranean formations, and particularly those which are offshore, the temperatures in the formations are very low. While delayed viscosity breakers such as alkali metal and ammonium persulfates, alkali metal chlorites and the like function very well to cause fracturing fluids to break at relatively high temperatures, at low temperatures the delayed viscosity breakers require very long times to break the fracturing fluids and as a result the delayed viscosity breakers are not useful.
Thus, there are needs for improved delayed viscosity breakers which function to quickly reduce the viscosities of fracturing fluids at low temperatures.